Date: Dec 29, 2012 7:49 AM
Author: Luis A. Afonso
Subject: Re: Polio, Salk vaccine

Follow-up


Less risky is to use the Chi-squared test.


____________Polio________no__________total___
_No_vaccin___115_______201113_____(201228)__
__Vaccin______33_______200442_____(200475)___
_total=______(148)______(401555)____(401703)___


Chi-squared (1df)= 45.1423_____
___pvalue=______ 1.832E-11___(OE-11 as well)


Conclusion : Salt vaccine is effective to prevent polio infeccion.

Luis A. Afonsoi